Method for pre-processing block based digital data

ABSTRACT

The present invention relates to a method for pre-processing block-based digital data, wherein a pre-processing step (S 5,  S 6 ) is performed for each digital pixel (X) based on a respective data filter arrangement or data filter matrix (Fk,j) for the respective data pixel (X) within at least one data block (DB) and wherein a step (S 5 ) of selecting, constructing and/or supplying said data filter arrangements or data filter matrices (Fk,j) is essentially based on operations of data shifting and/or register shifting only.

The present invention relates to a method for pre-processing block-baseddigital data and in particular to a method for pre-processingblock-based digital video data. More particular, the present inventionrelates to a method and a circuit for realizing a cash buffer forfiltering block-based digital data and in particular block-based digitalvideo data.

The present invention applies to the field of processing digital dataand in particular to the field of processing digital video data. Inknown video processing methods and video processing systems beforeprocessing said digital data and in particular said digital video datasometimes a data selection is necessary in the sense that provideddigital data or provided digital video data to be processed based on ablock structure have to be arranged and/or selected by building blocksof said digital data or said digital video data. Therefore, it isnecessary to filter the incoming or provided digital data or digitalvideo data in a two-dimensional manner, i.e. by using a digital spatialtwo-dimensional filter or two-dimensional FIR filter with respect to theprovided or incoming digital data items or digital data pixels.

It is an object of the present invention to provide a method forpre-processing digital data or digital video data and a system forrealizing said method, which have a particular simple and reliablestructure.

The object is achieved by a method for pre-processing block-baseddigital data according to the characterizing features of independentclaim 1. Preferred embodiments are defined within the dependentsubclaims. The object is further achieved by a system for pre-processingblock-based digital data according to claim 20 as well as by a computerprogrammed product and a computer-readable storage medium according toindependent claims 21 and 22, respectively.

The inventive method for pre-processing block-based digital data is inparticular designed for pre-processing block-based digital video data.According to the present invention it is provided that for at least onedata block of digital data for each data item or a data pixel a datasub-arrangement or data sub-matrix is provided, generated, and/or usedas an assigned data filter arrangement or data filter matrix. I.e. inmore detail: According to the present invention it is provided that forat least one data block of digital data—said data block being containedor embedded in a data arrangement or a data matrix of data items or datapixels—for each data item or a data pixel of said data items or datapixels of said at least one data block within said data arrangement ordata matrix a data sub-arrangement or data sub-matrix that is assignedfor or to said respective data item or data pixel within said respectivedata block of said data arrangement or data matrix is provided,generated, and/or used as a assigned data filter arrangement or datafilter matrix. Further, a pre-processing step is performed for each ofsaid data items or data pixels within said at least one data block basedon the respective data filter arrangement or data filter matrix for therespective data item or data pixel within said at least one data block.According to the present invention a step of selecting, constructingand/or supplying said data filter arrangements or data filter matricesis essentially based on operations of data shifting and/or registershifting only.

It is therefore a basic idea of the present invention to realize and/orprovide the data filter arrangements or data filter matrices that arenecessary for a step of pre-processing the data items or data pixels ofa given data block of digital data by using data shift operations and/orregister shift operations only. Therefore, only a single process of dataloading is necessary with respect to the respective data block and theembedding data arrangement. Further, the shift operations or registershift operations have a particular simple structure and can be realizedby compared simple technical means, thereby realizing a simple, reliableand less time-consuming strategy for selecting, constructing and/orsupplying the necessary data filter arrangements.

According to a preferred embodiment of the present invention saidrespective data item or data pixel and said assigned data filterarrangement or data filter matrix are chosen to be based on a certainpositional relationship with respect to each other and/or with respectto the respective data block to be pre-processed.

It is of particular advantage if said respective data item or data pixelis positioned in a central region of the respective assigned data filterarrangement or data filter matrix.

More advantageously, said respective data item or data pixel is thecentral data item or data pixel of the respective assigned data filterarrangement or data filter matrix.

According to a preferred embodiment of the inventive method forpre-processing block-based digital data said respective data arrangementor data matrix are chosen and designed to have a rectangular form of agiven certain number of lines or rows and of a given certain number ofcolumns of data items or data pixels.

It is of further advantage to design the respective data block to bepre-processed with a given certain number M of lines or rows and a givencertain number L of columns of M×L data items or data pixels.

It is of further advantage to choose or design said data filterarrangement or said data filter matrix with a rectangular form having agiven certain—in particular odd—number K of lines or rows and a givencertain—in particular odd—number J of columns of data items or datapixels.

According to a preferred embodiment of the inventive method forpre-processing block-based digital data said step of selecting,constructing and/or supplying said data filter arrangements and/or saiddata filter matrices and in particular said operations of data shiftingand/or register shifting are essentially based on and/or are essentiallyperformed using an embedding data block which contains and/or embedssaid respective data block to be pre-processed—or a copy thereof—andsaid data filter arrangements and/or data filter matrices—or copiesthereof—and which is common for all of said data filter arrangementsand/or for all of said data filter matrices assigned to each of saiddata items and/or data pixels of said data block to be pre-processed.According to the particular measure said embedding data block is used toevaluate and to pre-process the selected data block to be pre-processed.It is a further basic aspect of the present invention to choose anddesign the respective embedding data block. The data of said embeddingdata block has to be chosen and stored only one time. Based on theembedding data block the respective shifting operations or registershifting operations lead to the data filter arrangements or data filtermatrices in a straightforward and sequential manner.

According to a further aspect of the present invention said embeddingdata block is chosen and/or designed to have a rectangular form of M+K−1lines or rows and of L+J−1 columns of digital items or digital pixels ofsaid data arrangement and/or of said data matrix. Additionally oralternatively, for all data filter arrangements and/or for all datafilter matrices for a given data block to be pre-processed a common andfixed filter mask area within said embedding data block may be used forsaid step of selecting, constructing, and/or supplying said data filterarrangements and/or said data filter matrices.

Further additionally or alternatively, said filter mask arrangement maybe chosen to be simply connected corner block, in particular ofrectangular form and/or of K lines or rows and of J columns of dataitems or data pixels of said embedding data block.

According to a preferred embodiment of the inventive method forpre-processing block-based digital data said respective data block ispre-processed row by row or line by line, in particular starting with atop row or top line of said data block to be pre-processed and/or inparticular pre-processing the rows or lines of said data block in theirsequential order. Of course, the processing can also be performedstarting with a button row and pre-processing the rows of the data blockinverse to their sequential order. Alternatively also a pre-processingcolumn by column is possible either from left to right or from right toleft in their sequential order inverted to their sequential order,respectively.

In all these cases within each row or line (column) the respective dataitems or data pixels are pre-processed in their sequential order withrespect to the columns (rows or lines) of the data block to bepre-processed, in particular starting with a first or most left dataitem or data pixel in the respective row or line.

It is of further advantage when according to a further preferredembodiment of the present invention within said step of selecting,constructing and/or supplying said data filter arrangements and/or saiddata filter matrices an order is used which corresponds to the order ofpre-processing said respective data items and/or data pixels within saidrespective data block to be pre-processed. According to this measure adirect correspondence or assignment between the pixels of the data blockto be pre-processed and the data filter arrangements and/or data filtermatrices is realized in a particular simple and reliable manner.

According to a further preferred embodiment of the present invention theshift operations may be chosen from the group, which consists of thefollowing operations:

-   -   (a) All data items and/or data pixels of the embedding data        block are shifted one step to the left, i.e. in each line to the        next lower indexed column (j:=J−1) and in the case of a data        item and/or data pixel of a first column (j=1) to the last        column (j=L+J−1) of the next lower indexed row or line (k:=k−1).        The respective data item and/or data pixel is cancelled from the        embedding data block if it is in the first column (j=1) of the        first line (k=1).    -   (b) All data items and/or data pixels of the embedding data        block are shifted by one row or line to the top, i.e. for each        line (k=1, . . . , M+K−1) all data items and/or data pixels of        the last L−1 columns are shifted J steps to the left, i.e. to        the respective J-times lower indexed column (J:=J−J).        Simultaneously, for each but the first line (k=2, . . . , M+K−1)        all data items and/or data pixels of the first J columns (j=1, .        . . , J) are shifted to the last J columns (J=L, . . . , L+J−1)        of the next lower indexed row or line (k:=k−1). In the case of        the first line (k=1) the respective data items and/or data        pixels of the first J columns are cancelled from the embedding        data block.        According to the present invention the step of selecting,        constructing, and/or supplying said data filter arrangement        and/or said data filter matrices is realized by the following        steps:    -   The respective embedding data block is loaded.    -   The data block DB to be pre-processed is pre-processed by        starting with the most left upper data item and/or data pixel of        said data block DB to be pre-processed, i.e. with the data item        and/or data pixel of said data block DB to be pre-processed        having row and column indices 1 and 1 within the data block DB        to be pre-processed. This is done by using the section of the        embedding data block as a respective data filter arrangement        and/or data filter matrix which is given by or corresponding to        said common filter mask area which is in particular in a fixed        spatial relationship to the embedding data block for all data        filter arrangements and/or for all data filter matrices, i.e.        for all pixels within said data block to be pre-processed.    -   The further data blocks and/or data pixels are pre-processed by        applying the shift operation (a)—as described above—(L−1) times        for all M lines, whereas the shift operation (b)—as described        above—is applied (M−1) times. In other words, the further data        blocks and/or data pixels are pre-processed by sequentially        (M−1) times applying for each line (L−1) times the shift        operation (a) followed by an shift operation (b) and by using        the respective section of the embedding data block as a        respective data filter arrangement and/or data filter matrix        which is given by and/or corresponding to said common filter        mask area after each of said shift operation (a) and after each        of said shift operation (b).

According to a further preferred embodiment a shift register is used torealize and/or to store said embedding data block and in particular saidcommon filter mask area. Said shift register has in particular M+K−1lines or rows and L+J−1 columns of pixel registers or pixel storingelements.

In this case each of said pixel storing elements or pixel registers maybe provided with a 3-input multiplexers as to realize a selection of oneof the above described shift operations (a) and/or (b).

It is of further advantage to control the inventive method forpre-processing block-based digital data by a state machine and/or by astate machine process.

According to a further aspect of the present invention a system,apparatus, or device is provided which is adapted and/or designed torealize and/or to perform the inventive method for pre-processingblock-based digital data and the steps thereof. According to anotheraspect of the present invention a computer program product is providedwhich comprises computer program means being adapted to realize and/orto perform the inventive method for pre-processing block-based digitaldata and/or the inventive system for pre-processing block-based digitaldata when it is executed on a computer, a digital processing meansand/or the like.

Additionally, a computer readable storage medium is provided andcomprises the inventive computer program product.

In the following these and further aspects of the present invention willbe explained in further detail:

The present invention particularly relates inter alia to a method and toa circuit of cache buffering for filtering block based video data.

The here described invention applies to a digital video processingsystem, where each field out of a sequence of video fields is split intoa number of rectangular blocks with a size of L×M pixels each. Suchvideo processing systems are used for e.g. motion estimation or formatconversion applications. This is according to the fact that block basedvideo field processing helps minimizing the data access bandwidth to themain video memory. This invention describes the method and structure ofa cache buffer that enables a simple processing of video blocks with asize of L×M pixels by a digital spatial 2D FIR filter with J×K parallelinput pixels e.g. used for noise reduction or picture sharpnessimprovement. The here described cache buffer has a simple and regularstructure, which makes it easy to implement in programmable logic orASIC.

This invention describes a method of filtering video data in a blockbased video processing system by a spatial 2D filter. A possiblesolution of the problem could be, to store the video data in a fixedregister-matrix and select the filter input data by multiplexers.However this approach would increase the number of logic gates andsignal delay time significantly, especially at filters with manyparallel input pixels, where wide-range multiplexers are needed. Thehere described idea of storing pixel data in a shift register, whoseoutput lines are directly connected to the input of the filter, helps tokeep the number of logic gates low and allows an easy adaptation todifferent filter sizes. Due to the scaleable architecture, the signaldelay time and therefore the system speed are not influenced by thefilter size.

The present invention therefore covers inter alia a shift register withabove mentioned properties and structure and a state-machine to controlthe switching behavior of this shift register.

In the following these and further aspects of the present invention willbe described in further detail by taking reference to the accompanyingfigures.

FIG. 1 is a schematical block diagram demonstrating several basicaspects of the inventive method for pre-processing block-based digitaldata.

FIG. 2 demonstrates some relationships of the different data structuresused within the present invention.

FIG. 3-4D schematically describe further aspects of the data structuresused within the present invention.

FIG. 5 is a schematical block diagram of a state machine or a statemachine process used within the present invention.

FIG. 6A, B are schematical diagrams of a shift register and of itsoperation which both can be used to realize the present invention.

FIG. 7A, B demonstrate by means of schematical block diagrams data shiftoperations, which can be used within the present invention.

FIG. 8A, B are schematical block diagrams demonstrating further detailsof preferred embodiments of the present invention.

In the following, similar elements, structures and functionalities aredenoted by the same reference symbols. A detailed description is notgiven in each case of their occurrence.

FIG. 1 is a schematical block diagram that elucidates some basic aspectsof the inventive method for pre-processing block-based digital data.

Within a first step S1 said digital data to be pre-processed arereceived and/or supplied in the form of a digital data stream DS. Withina second step S2 a certain data block DB to be pre-processed isselected. Within a third step S3 an embedding data block EDB isgenerated and/or initialized. Any shift operation or data shiftoperation according to the present invention is performed on theembedding data block EDB which is a copy of a respective data sectioncontained in or embedded in the received data stream DS. Within a fourthstep S4 a filter mask area FMA is generated, selected, and/or assigned.Said filter mask area is common for all pixels of the selected datablock DB to be pre-processed and consequently common for all data filterarrangements and/or data filter matrices for each of said pixels withinsaid data block DB on the basis of which the pre-processing of each ofsaid respective pixels within said data block DB is performed within afollowing step S5. Step S5 may be followed by an optional pre-processingstep S6 which is indicated in FIG. 2. After having finished theprocessing of the entire data block DB it is checked on whether or not afurther data block DB has to be pre-processed in which case theprocessing of FIG. 1 branches again to the second step S2 of selecting afurther data block DB to be pre-processed. Otherwise, the process shownin FIG. 1 ends.

FIG. 2 schematically describes the relationship between the differentdata structures used within the inventive method for pre-processingblock-based digital data. Digital data are—as already indicated withrespect to FIG. 1—as a digital data stream DS. After pre-processing thedigital data contained in the digital data stream DS a processed digitaldata stream PDS is obtained. The digital data stream DS is built up bydata fields DF1 . . . , DFn. Each data field DF1 . . . , DFn is built upby a data matrix DM1, . . . , DMn. In the situation shown in FIG. 2 acertain given data field DF1 is subjected to a pre-processing step.Therefore the respective data matrix DM1 is selected. Within said datamatrix or data arrangement DM1 a certain data block DB to bepre-processed is selected. The respective data arrangement or datamatrix DM1 and therefore the data block DB to be pre-processed is builtup by respective data items or data pixels DPk,j which are selected asselected data items or data pixels X in their sequential order.

It is important to choose and select an embedding data block EDB whichis a copy of the respective data region within the respective selecteddata matrix DM1 of the provided data stream DS. The embedding data blockEDB is chosen and designed to be an embedding for the selected datablock DB to be pre-processed as well as for the respective data filterarrangements or data filter matrices Fk,j which have to be constructedfor each of the selected pixels X, X′ of the selected data block DB,DB′. Additionally a filter mask area FMA is selected within theembedding data block EDB at a fixed position. Therefore a common filtermask area FMA for all possible data filter arrangements and/or datafilter matrices Fk,j is built up. The data which coincide with therespective filter mask area FMA are copied and used as said data filterarrangement and/or as said data filter matrix Fk,j for each of thepixels X, X′ which are selected from the data block DB, DB′.

By using data shift operations only which are applied to the embeddingdata block EDB the copied data within the embedding data block EDB areshifted in a way that the fixedly positioned filter mask area FMA seesthe respective data within the embedding data block which correspond tothe respective data filter arrangement and/or the respective data filtermatrix Fk,j which corresponds to the selected data item or data pixel X,X′ of the plurality of pixels DPk,j within the copy DB′ of the datablock DB, thereby selecting and providing the data section defined bythe filter mask area FMA within the embedding data block EDB as a datafilter arrangement or data filter matrix Fk,j on the basis of which thepre-processing step S5 of FIG. 1 is performed so as to yield on thebasis of said data filter arrangement or data filter matrix Fk,j apre-processed selected data item or data pixel X which corresponds tothe respective pre-processed data pixel DPk,j within the pre-processeddigital data stream PDS.

These relationships hold for each of said selected data pixels or dataitems X within the selected data block DB to be pre-processed, andfurther for all selected data blocks DB of a selected data arrangementor data matrix DM1 constituting the data fields DF1 within the receiveddigital data stream DS.

FIGS. 3 to 4D schematically describe several aspects of the signalsand/or data structures used within the present invention.

The pre-processing of a data block of L×M data pixels DPk,J by a2-dimensional J×K sized FIR filter is shown in FIG. 3.

As an example a data block DB of 8×4 pixels is filtered by a 7×5 filteror data filter arrangement or data filter matrix Fk,j. This means thatfor each pixel X of the data block DB to be pre-processed J×K=35parallel input data pixels DPk,j are needed to be processed to give oneresultant pre-processed data pixel PX in a processed data block PBK saidpre-processed data pixel PX corresponding to said given data pixel X.The resultant pixel PX is usually located in the center of the J×Kmatrix, therefore J and K are usually odd numbers. The J×K filter Fk,jmoves over the L×M data block DB by shifting the data pixels DPk,jthrough the fixedly positioned filter mask area FMA. This is realized inthe following way:

The pre-processing starts with the upper left pixel of the L×M datablock DB. The processing order of the L×M data pixels is from left toright. At the end of each line or row, the pre-processing continues withthe first pixel of the next line until all L×M pixels are processed.Dependent on the values J and K of the filter, data pixels from adjacentblocks are involved in the processing. Therefore, a total amount of[(L+J)−1]×[(M+K)−1] data pixels is needed to process a block of L×M datapixels.

All mentioned shift operations and their effect on the filter input aredemonstrated in FIG. 4A-4D.

The example shows the embodiment of an 8×4-pixel video-processing blockwith a 7×5 FIR-filter mask or filter mask area FMA. Includingoverlapping pixels from adjacent blocks, a total of 14×8 pixels areinvolved in the processing. The first 7 pixels of the first 5 lines areconnected to the 7×5 filter. FIG. 4A shows the initial state of theshift register after reload operation. New pixel positions after thefirst shift operation are shown in FIG. 4B. The second pixel of eachline now moved to the first position of the 7×5-filter mask, the thirdpixel to the second position and so on. This is equivalent to moving the7×5-filter mask one position to the right. The pixel shift is continued(L−1) times, until the last pixel of the first line is processed. At theend of the first line, pixels are in the position shown in FIG. 4C. Nowthe filter mask jumps to the beginning of the next line. As thevideo-processing filter has a width of J=7 pixels, all pixels inside theshift register are therefore shifted left by 7 positions. This bringsthe pixels of the former second line to the first line of the 7×5-filteras is shown in FIG. 4D. Then processing continues with the second lineof the 8×4 block and so on, until all pixels in the 8×4 block areprocessed.

All shift and reload operations may be controlled by a state-machine orstate machine process as is shown in FIG. 5.

During “Load Reg”-state all registers of the [(L+J)−1]×[(M+K)−1] arrayare reinitialized. Parallel or sequential register reload is possible.After register loading, the state-machine switches to the “Shift by 1position”-state. In this state, all pixels are shifted one position tothe left, which means that they are replaced by their right neighborpixel. Shifting pixels left is equivalent to moving the J×K filter inFIG. 3 one position to the right. After processing all pixels of thefirst line, processing continues with the first pixel of the secondline. This is achieved by shifting all pixels J positions to the left.Afterwards the state-machine switches back to the “Shift by 1Position”-state until the second line is processed and so on. At the endof the last line in an L×M block, the state-machine receives the triggercondition “next block”, which means another restart of the whole blockprocessing cycle.

A structure of a possible cache buffer realizing the embedding datablock EDB is shown in FIG. 6A.

Each box represents a pixel of n parallel bits of e.g. typical values of8 or 10 bits per pixel. The first J pixels of the first K lines aredirectly connected to the J×K filter input. The cache buffer isorganized as shift register. It consists of [(M+K)−1] lines with eachline containing [(L+J)−1 ] pixels. All lines and pixels are connected ina way that the last pixel of a line is followed by the first pixel ofthe next line and so on. Instead of moving the J×K filter over the L×Mblock, which would need large multiplexers at the filter input, the J×Kfilter mask always stays at the same position relative to the shiftregister, while the pixels are shifted. After each shift operation, thepixels in the J×K filter input array move to the new position needed forthe calculation of the next result pixel. A 3-input multiplexer isassigned to each pixel in order to select the appropriate shiftoperation.

FIG. 6B illustrates the respective operation (a) and the respectiveoperation (b) as described above.

Three different operations are possible:

1. Load new cache content, i.e. a new data block DB to be pre-processed.Thereby, replace all data pixels by completely new values.

2. Process or pre-process a next data pixel of a given data block DB.Therefore, shift all data pixels one position to the left, wherein thefirst data pixel of each line is shifted to the end of the upper line asis shown in FIG. 7A.

3. Perform a line jump. This is done by shifting all data pixels Jpositions to the left, wherein the first J data pixels of each line orrow are moved to the last J positions of the upper line or row as isshown in FIG. 7B.

The register loading strategy depends on the video data processing speedof the implemented filter.

Blank positions inside the shift register can be refilled continuouslywith new video data of the next processing block as shown in FIG. 8A.After processing the last pixel of the previous video block, previousblock data can be replaced by the block data of the next processingblock. During the time needed for video data replacement, video signalprocessing has to be interrupted in order to avoid invalid filter inputdata mixed from the previous and next video block.

If it is not possible to interrupt video data processing during datareplacement time, at least some lines of next block video data have tobe copied from a swap buffer to the filter processing area of the shiftregister in a single step operation. In order to have enough next blockvideo data in the swap buffer, some additional helper registers might benecessary. After performing the swap operation the shift register isshown in FIG. 8B. All next block data have been copied to the processingarea of the shift register and the processing of the first video pixelof the next video block can be started. In order to keep the shiftregister running without further interruption, blank positions of theshift register have to be filled with the rest of next block video data.

REFERENCE SYMBOLS

-   B blank pixel-   DB data block to be processed/pre-processed-   DB′ copy data block to be processed/pre-processed-   DP, DPk,j data item/data pixel belonging to row/line k and column j-   DP′, DPk,j′ copy of data item/data pixel belonging to row/line k and    column j-   DS input data stream of digital data to be processed/pre-processed-   DS′ output or processed/pre-processed data stream-   DF, DF1 data field of data stream; (1=1, . . . , n)-   DF′, DF1′ processed/pre-processed data field of    processed/pre-processed data stream-   DM, DM1 data arrangement/matrix for data field DF, DF1; (1=1, . . .    , n)-   DM′, DM1′ processed/pre-processed data arrangement/matrix for data    field DF, DF1; (1=1, . . . , n)-   EDB embedding data block, shift register area/block-   Fk,j data filter arrangement/matrix belonging to data pixel DPk,j-   FMA filter mask, filter mask area-   J number of rows/lines of data filter arrangement/matrix Fk,j and/or    of filter mask area FMA-   K number of columns of data filter arrangement/matrix Fk,j and/or of    filter mask area FMA-   L number of columns of data block DB, DB′, PDB-   M number of rows/lines of data block DB, DB′, PDB-   PDB processed/pre-processed data block-   PDP, PDPk,J processed/pre-processed data item/pixel belonging to    row/line and column j-   X selected data item/pixel of data block DB-   X′ copy of selected data item/pixel of data block DB′

1. Method for pre-processing block-based digital data, in particularblock-based digital video data, wherein for at least one data block (DB)of digital data said data block (DB) being contained or embedded in adata arrangement or data matrix (DM1, . . . , DMn) of data items and/ordata pixels (DPk,j) for each data item or data pixel (X) of said dataitems or data pixels (DPk,j) of said at least one data block (DB) withinsaid data arrangement or data matrix (DM1, . . . , DMn) a datasub-arrangement or data sub-matrix assigned for or to said respectivedata item or data pixel (X) within said respective data block (DB) ofsaid data arrangement or data matrix (DM1, . . . , DMn) is used as aassigned data filter arrangement or data filter matrix (Fk,j), wherein aprocessing step (S5, S6) is performed for each of said data items ordata pixels (DPk,j) based on the respective data filter arrangement ordata filter matrix (Fk,j) for the respective data item or data pixel (X)within said at least one data block (DB), and wherein a step (S5) ofselecting, constructing and/or supplying said data filter arrangementsand/or data filter matrices (Fk,j) is essentially based on opera-tionsof data shifting and/or of register shifting only.
 2. Method accordingto claim 1, wherein said respective data item or data pixel (X) and saidassigned data filter arrangement or data filter matrix (Fk,j) are chosento be based on a certain and/or fixed positional relationship withrespect to each other and with respect to said respective data block(DB).
 3. Method according to claim 1, wherein said respective data itemor data pixel (X) is in a central region of the respective assigned datafilter arrangement or data filter matrix (Fk,j).
 4. Method according toclaim 1, wherein said respective data item or data pixel (X) is thecentral data item or data pixel of the respective assigned data filterarrangement or data filter matrix (Fk,j).
 5. Method according to claim1, wherein said respective data arrangement or data matrix (DM1, . . . ,DMn) has a rectangular form of a given certain number of lines or rowsand of a given certain number of columns of data items or data pixels(DPk,j).
 6. Method according to claim 1, wherein said respective datablock (DB) is chosen and designed to have a given certain number M oflines or rows and a given certain number L of columns of M×L items ordata pixels (DPk,j).
 7. Method according to claim 1, wherein said datafilter arrangement or said data filter matrix (Fk,j) has a rectangularform with a given certain—in particular odd—number K of lines or rowsand a given certain—in particular odd—number J of columns of data itemsor data pixels (DPk,j).
 8. Method according to claim 1, wherein saidstep (S5) of selecting, constructing and/or supplying said data filterarrangements and/or said data filter matrices (Fk,j) and in particularsaid opera-tions of data shifting and/or said operations of registershifting are essentially based on and/or are essentially performed withrespect to an embedding data block (EDB) which contains and/or embedssaid respective data block (DB) to be pre-processed—or a copy (DB′)thereof—and said data filter arrangements and/or data filter matrices(Fk,j) and which is common for all data filter arrangements and/or datafilter matrices (Fk,j)—or a copy (Fk,j′) thereof—assigned for each ofsaid data items or data pixels (X) of said data block (DB) to bepre-processed.
 9. Method according to claim 8, wherein said embeddingdata block (EDB) is chosen and/or designed to have a rectangular form ofM+K−1 lines or rows and of L+J−1 columns of data items or data pixels(DPi,j) of said data arrangement and/or of said data matrices (DM1, . .. , DMn).
 10. Method according to claim 8, wherein for all data filterarrangements and/or for all data filter matrices (Fk,j) for a given datablock (DB) to be pre-processed a common and fixed filter mask area (FMA)within said embedding data block (EDB) is used for said step (S5) ofselect-ing, constructing and/or supplying said data filter arrangementsand/or data filter matrices (Fk,j).
 11. Method according to claim 10,wherein said filter mask area (FMA) is chosen and/or designed to be asimply connected corner block, in particular of rectangular form and/orof K lines or rows and of J columns of data items or data pixels (DPk,j)of said embedding data block (EDB).
 12. Method according to claim 1,wherein said respective data block (DB) is pre-processed row by row, inparticular starting with a top row of said data block (DB) to bepre-processed and/or in particular by pre-processing the rows or linesof said data block (DB) in their sequential order.
 13. Method accordingto claim 12, wherein within each row or line the respective data itemsand/or data pixels (X) are pre-processed in their sequential order withrespect to the columns of the data block (DB) to be pre-processed, inparticular starting with a first or most left data item and/or datapixel (X) in the respective row or line.
 14. Method according to claim1, wherein within said step (S5) of selecting, constructing and/orsupplying said data filter arrangements and/or said data filter matrices(Fk,j) an order is used which corresponds to the order of pre-processingsaid respective data items and/or data pixels (X) within said respectivedata block (DB) to be pre-processed.
 15. Method according to claim 14,wherein the data shift operations and/or the register shift operationsare chosen from the group which consists from the following operations:(a) shift all data items and/or data pixels (DPk,j) of the embeddingdata block (EDB) one step to the left, i.e. in each line (k=1, . . . ,M+K−1) to the next lower indexed column (j:=j−1), in the case of a dataitem and/or a data pixel (DPk,j) of a first column (j=1) to the lastcolumn (j=L+J−1) of the next lower indexed row or line (k:=k−1), orcancel the respective data item and/or data pixel (DPk,j) from theembedding data block (EDB) if it is in the first column (j=1) of thefirst line (k=1), and (b) shift all data items and/or data pixels(DPk,j) of the embedding data block (EDB) one row or line to the top,i.e. for each line (k=1, . . . , M+K−1) shift all data items and/or datapixels (DPk,j) of the last L−1 columns J-times to the left, i.e. to therespective J-times lower indexed column (j:=j−J) and simultaneously foreach but the first line (k=2, . . . , M+K−1) shift all data items and/ordata pixels (DPk,j) of the first J columns (j=1, . . . , J) to the lastJ columns (j=L, . . . , L+J−1) of the next lower indexed row or line(k:=k−1), for the first line (k=1) cancel the data item and/or datapixel (DPk,j) of the first J columns (j=1, . . . , J).
 16. Methodaccording to claim 15, wherein the step of selecting, constructingand/or supplying said data filter arrangements and/or said data filtermatrices (Fk,j) is realized by the following consecutive steps:generating and/or loading (S3) the respective embedding data block(EDB), pre-processing (S5, S6) the data block (DB) to be pre-processedstarting with the most left upper data item and/or data pixel (DPk,j),i.e. with the data item and/or data pixel (DPk,j) with k=1, j=1 by usingthe section of the embed-ding data block (EDB) as a respective datafilter arrangement and/or data filter matrix (Fk,j) which is given byand/or corresponding to the common filter mask area (FMA), andpre-processing (S5, S6) the further data items and/or data pixels(DPk,j) by sequentially (M−1)-times applying for each line (L−1)-timesthe shift operation (a) followed by an shift operation (b), and by usingthe section of the embedding data block (EDB) as a respective datafilter arrangement, and/or data filter ma-trix (Fk,j) which is given byand/or corresponding to the common filter mask area (FMA) after each ofsaid shift operations (a) and (b).
 17. Method according to claim 1,wherein a shift register—in particular with the M+K−1 lines or rows andL+J−1 columns of pixel registers—is used to realize and/or to store saidembedding data block (EDB) and in particular said common filter maskarea (FMA).
 18. Method according to claim 17, wherein each pixelregister if provided with a 3-input multiplexer so as to select one ofthe shift operations (a) and/or (b).
 19. Method according to claim 1,which if controlled or controllable by a state machine or a statemachine process.
 20. System for pre-processing block-based digital data,which is adapted and/or designed to realize the method forpre-processing block-based digital data according to claim
 1. 21.Computer program product, comprising computer program means which isadapted to realize and/or to per-form the method for pre-processingblock-based digital data according to claim
 1. 22. Computer readablestorage medium, comprising a computer program product according to claim21.